TOLONGIN YA. PAKAI CARA MOHON.NO 28

A + B + C = 180
7x - 3 + 5x + 5 + 4x + 2 = 180
16 x + 4 = 180
16 x = 176
x = 11

sehingga :
A = 7x - 3 = 7 (11) - 3 = 77 - 3 = 74
B = 5x +  = 5 (11) + 5 = 55 + 6 = 60
C = 4x + 2 = 4 (11) + 2 = 44 + 2 = 46

urutan : BC, AB, AC